Can't get div to expand height to include content inside

I can't figure out how to get the height of my middle-container div to expand to fit the data inside. I'm getting lost in suggestions like height:100%, etc. Anyone figure out what css I need to add to fix the following:

http://www.tippycanoetoo.com/pillows-rugs-throws.html

http://www.开发者_如何转开发tippycanoetoo.com/emma-20-5-square-throw-pillow-1.html

(It appears fine in Firefox & IE7, but not Chrome, Safari, & IE8 - it temporarily is fine in IE8 b/c I set the compatibility mode to IE7 in the head.)

Add overflow:hidden; to .middle-container or .middle

See clearing floats for an explanation